ABSTRACT The Oncology Tissue Services (OTS) Core provides a number of technologies, services and scientific consultation to support the research of the Sidney Kimmel Comprehensive Cancer Center (SKCCC) members and other Johns Hopkins University (JHU) investigators. The Core was formerly known as the Tissue Microarray Core (TMA), when it provided TMA-related services, digital slide scanning and analysis, and routine histology services. With the addition of immunohistochemistry (IHC), immunofluorescence (IF) in situ hybridization (ISH) and the incorporation of the cytogenetics Core, the Core was renamed. It now provides traditional G-band metaphase analysis and FISH technologies, services added to this Core from a previous SKCCC CCSG Core. These expanded services enhance the ability of SKCCC researchers to perform tissue- based biomarker studies. The OTS Core has constructed greater than 826 TMAs for 55 investigators, containing tumor and normal tissue from most major organs. It has provided more than 80 new antibody workups and cored more than 2,500 blocks for RNA/DNA studies. It continues to provide essential cytogenetics services. Users published more than 104 manuscripts involving this resource since the last funding period began. In recent years, there has been tremendous growth in the service of providing tissue cores from FFPE tissue blocks for RNA and DNA molecular analyses. Instrumentation and expertise are available to automatically capture high-resolution digital images of both standard histology/IHC-based slides and TMA slides. The OTS Core obtained an automated slide stainer to convert laboratory discoveries of novel protein staining into clincal biomarkers. The Core provides Web-based software tools and two back-end databases (TMAJ/Spectrum) to facilitate all facets of research involving TMAs, routine slides and quantitative image analysis. The specific aims of this Core are: Aim 1: Provide affordable, high-quality histology, immunohistochemistry, cytogenetics, nucleic acid harvesting from tissues, digital slide scanning and analysis, and tissue microarray construction services. Aim 2: Identify and develop new technologies to support and speed translational research in cancer, including automated in situ hybridization and clinical translation of research immunohistochemistry discoveries. Aim 3: Support the Research Programs and respond to the needs of its users to by working with specific investigators on new protocols, procedures and custom procedures to meet their evolving histology, immunohistochemistry and slide scanning requirements. SKCCC Managed Core Reporting Period: Jan. 1, 2015, to Dec. 31, 2015